TheNimrod

Hi folks. I've been trying to find and have read any related post I can find for my problem but nothing seems to pop up that matches my current problem.

I have an 2002 Tacoma 3.4 V6 SR5 double cab 4x4 Automatic with 135,000 miles.
About 3 years ago the check engine light came on and I had Autozone pull the code P1135. The guy told me not to worry about it because if the truck was running ok without it then it's probably related to California emissions crap that don't apply here in our state. I live in SC.
So... I've been driving it for about 3 years with the check engine light on with no major problems other than 17mpg which is close to what I've always gotten anyhow.
This all changed about 4 weeks ago when the truck started to loose a lot of power and needed to down shift a lot to Climb small hills or accelerate quickly. I took it back down and had them pull the codes again and as expected the P1135 code was there. This time the guy (different guy from the first time) told me it was the A/F sensor and it should be replaced. He looked the part up on there system and I bought a Bosch Wideband A/F sensor part # 12613 (F00E260829). I took it home and installed it and it took about 40 miles the next day and the check engine light went off. The difference in performance was amazing! Fuel mileage didn't come up much but it drove like a brand new truck again with lots of power. I was one happy camper!
Well... That lasted about 2 weeks and the Check engine light is back on and I've noticed a loss of power again. I took it back to Autozone and sure enough they pulled P1135 again.

So... What do I do? They will let me exchange it for a new one but I'm worried that something else is wrong and could "pop" the next one the same way. I found a post about checking the heater resistance of the A/F sensor and I will check that first, but based on how it improved after replacing it then went down hill again I'm thinking that something may have fried the new sensor.

Any help would be much appreciated.

TheDurk

You will probably have better luck with the OEM Denso's. Bosch doesn't play well with Toyotas. Get the Denso part number here:

http://www.densoaftermarket.com/catalog/

Then go find it on Amazon. I would also clean your plug contacts. If the Bosch heater resistance tests good, then you want to verify your sensor to ECU wiring. I think the FSM tells you how to do that.

TheNimrod

So you're thinking it was a bad sensor and nothing else could have caused it to die like that?

Thanks for the help!

mt_goat

I'd probably go to the FSM (pick your's out here: http://www.ttora.com/forum/showthread.php?t=59089) and look up that code and see the check list of things that can cause it.

TheDurk

P1135 is low or high current on sensor resistance circuit. Possible causes are open or short in sensor resistance heater and sensor wiring to ECU, as I stated. Go ahead, look it up....(but I agree with the approach).

TheDurk

It's either a bad sensor, the wrong sensor, or bad wiring/connection. Way down on the list is the ECU overloading the heater by sending the wrong voltage and thus causing it to die. I have never heard of that, but it's the only other thing I can think of--the FSM doesn't even consider that possibility.. P1135 is very specific, unlike a lot of other codes that have a laundry list of causes.

mt_goat

Ok, good to know. I did try to look it up but I couldn't find that code in the FSM diagnostics section. Since it wasn't my problem I didn't look real hard though

TheNimrod

Thanks for the link goat! Mind you that I'm not a big time wrencher but I try like hell. lol Looking into that code was a little fun, apparently they changed it from P0134 *5 to P1135 a few years back. That was headache #1. After finding it in the FSM it think I feel headache #2 coming. lol I think they listed every thing on the truck as a possible cause. What makes this even worse is the fact I don't know what or where half that crap is. lol

In the list below from top to bottom am I safe to assume that 1,2,3 & 5 are all related to the A/F sensor? And is it possible to just wave a magic wand over the truck to fix the rest of them? lol It's gona be a long weekend.

I did get a hold of the autoparts store and they are ordering a Denso for me and will have it tomorrow morning. They said to bring back the bad Bosch sensor and they'll exchange it for the Denso.

Thanks for the help!

P0134 *5 (Now P1135)
(DI–278) Oxygen (A/F) Sensor Circuit No Activity Detected (Bank 1 Sensor 1)


Open or short in A/F sensor (bank 1 sensor 1) circuit
A/F sensor (bank 1 sensor 1)
A/F sensor heater
EFI main relay
A/F sensor heater and relay circuit
Air induction system
Fuel pressure
Injector
Gas leak in exhaust system
PCV hose connection
PCV valve and hose
ECM

Edit: I need to type faster cause Durk had already posted more info for me before I could hit submit. lol

Thanks Durk! Now I gotta read it again and see what questions I'll have. lol

TheDurk

That one is pretty fresh in my mind. It's right at the end of the engine codes. Now that you forced me to check, I can confirm the procedure for checking the connection at the ECU bus IS spelled out in there.

TheDurk

Hehe, I'm watching you. P1135 is JUST the heater circuit. I think what happened is they split the heater DTC from the rest of the front sensor issues--so I don't think those other causes apply to your case. I'm going off a '99 4Runner paper FSM. Look at something more recent, maybe the 2002 4Runner which is on-line.

mt_goat

Yeah I agree, its different than a P0134.

TheNimrod

Ok... So the first thing I should do is check the wire/connection. Correct?
Then if everything looks good then check the ohms on the heater wires. That will tell me if the sensor is shot. Right?
If it fails the ohm check then replace the sensor?

Thaks again for the help.

TheDurk

Sounds like a plan. The other way around works, too. My feeling is it is more likely sensor will fail test and wiring is ok. Up to you...good luck.

TheNimrod

Cool. Thanks for the help and I'll let you know how I make out.

mt_goat

If you need a Denso sensor check URD's site out: http://www.urdusa.com/More-Products-...v759prs4t9c7p7

TheNimrod

Well.... I replaced the the Bosch sensor with a Denso and pulled the EFI fuse to clear the CEL. Before I returned the Bosch sensor I checked the ohms and it read good at 0.9 ohms.

The CEL stayed off for about 500 miles (4 or 5 days) and it was running great with lots of power and my MPG raised to the best it's ever been (19.2mpg).

Now the CEL is back on and I just had Autozone pull the code P0171 (lean fuel bank 1) or something like that. It feels like the power is starting to drop off again as well.

Several months ago I replaced my fuel filter and cleaned the MAF sensor and sprayed seafoam straight into an vacuum line to suck it into the engine. I've been using a K&N high flow air filter for several years as well. Other than these things, that's all I have done to the truck in case any of that helps.

Any iders what the hell I should do or check now?

Thanks

mt_goat

This is just a guess, but clean the MAF and if you can go to a dry air filter (K&N can leave a oil residue on the MAF). I like the stock air filter myself, flows well enough for me to get 10.5 psi of boost.

TheNimrod

Ok. I'll give that a shot and see if it works.

Thanks

4wd_mofo

Yo Nimrod, this fix your issue? I have the same problem, P1135, replaced the O2 with a denso, new plugs/wires, clean maf, cleaned TB and took apart IAC and cleaned that out, seafoam, new fuel filter and even went as far as a new ECU and im still throwing the P1135 CEL. i have a flow master 40 with stock piping and stock K&N intake filter with elbow mod. Help Help!!!

BigBallsMcFalls

leaving a p1135 unfixed [by replacing the sensor] can lead to severe engine damage
and even an internal manifold fire/engine fire from soot burning off

it is nothing to screw around with. rear O2 sensor, OK ignore that, But 1135 is a/f sensor
and it is critical for it to always function properly.